Suppression and potentiation of expression of delayed-type hypersensitivity by dextran sulphate.

Dextran sulphate delays the onset, or even completely suppresses the expression in mice of DTH or SRBC when administered via a route different from that of eliciting antigen. However, DS injected together with the eliciting antigen potential the expression of DTH. Dextran showed no effect on DTH. Cell transfer experiments suggest that the targets for the action of DS are the accessory cells (monocytes) and not the T-effector cells. As shown, using polystyrene latex particles and lipopolysaccharide from E. coli, trapping and perhaps activation of the trapped accessory cells rather than toxic effects of DS are responsible for these phenomena.